APPARATUS FOR PROVIDING OPTICAL RADIATION

摘要

The invention relates to a cladding-pumped optical device (40), comprising: an optical fibre (41) and pumps (44), wherein the optical fibre (41) comprises a core having a refractive index n1 and a pedestal having a refractive index n2, and wherein the optical fibre (41) includes a first cladding made of glass having a refractive index n3 surrounding the pedestal, wherein n1 is greater than n2, n2 is greater than n3, wherein the optical device (40) is cladding pumped by coupling pump radiation into at least the first cladding (5), and wherein signal light scattering or leaking from the core is captured and guided by the pedestal and therefore not routed back into the pumps (44).